JP2010156352A - Actuator having small diameter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the bending of an actuator having a small diameter due to an unbalanced load and to provide an actuator having a small diameter for a medical or industrial manipulator that requires highly accurate control. <P>SOLUTION: The actuator having a small diameter includes a displacement sensor having a folded structure that includes a first sensor part and a second sensor part. The first sensor part is arranged parallel to the center axis of the actuator, and the second sensor part is arranged axially symmetric with the positions of the first sensor part about the central axis on the line segments that perpendicularly intersect the central axis, and thereby the occurrence of an unbalanced load is suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a small diameter actuator. The present invention also relates to a thin manipulator including the thin actuator as a drive mechanism.

  Effective use of small-diameter actuators for local operations such as gripping, excision, connection, measurement, and marking of various objects that exist in remote locations, especially in narrow lumen regions It is a means. For example, displacement detection is indispensable when incorporating a pneumatically controlled actuator into a drive mechanism as a small-diameter actuator. However, even if the pneumatic actuator itself can be reduced in size and weight, the position detection mechanism uses laser displacement. Since it is necessary to attach a meter, a potentiometer, etc., it was difficult to reduce the size and weight of the entire system (Patent Document 1).

In addition, there is a case where a rubber artificial muscle actuator is used as a drive mechanism for a medical or industrial manipulator, and in this case, it is a problem to reduce the diameter of the insertion arm, but when the position detection mechanism is externally attached, It has been difficult to achieve a sufficiently small diameter. In particular, in the case of a medical manipulator, since it is used by being inserted into the abdominal cavity, it was necessary to adopt a structure in which the displacement sensor and the wiring are difficult to touch the living tissue. It has been difficult to adopt a structure that is incorporated in an insertion portion of a certain degree and is difficult to touch a living tissue.
JP 2005-95989 A

  An attempt was made to install a conductive thin film on the surface of the pneumatic actuator in order to solve the above problems, and it was found that the actuator body was subjected to an uneven load and bent, which hindered precise control. Accordingly, an object of the present invention is to provide a small-diameter actuator for preventing a bending of the actuator due to an uneven load and realizing a small-diameter medical or industrial manipulator requiring high-precision control.

  That is, the present invention includes a displacement sensor having a folding structure constituted by first and second sensor portions, the first sensor portion being arranged in parallel to the central axis of the actuator, and the second sensor The portion is arranged so as to be axially symmetric with respect to the central axis on a line segment perpendicular to the central axis from each position of the first sensor unit, thereby suppressing the occurrence of uneven load A small-diameter actuator is provided.

  The present invention also includes the small-diameter actuator, an insertion arm having the small-diameter actuator therein, and an operation tool attached to a tip of the insertion arm, and the operation tool is driven by the small-diameter actuator. A thin manipulator characterized by being controlled by expansion and contraction of an actuator.

  Furthermore, the present invention provides a thin manipulator comprising two or more small diameter actuators, each actuator being individually controlled.

  By the small diameter actuator of the present invention, bending due to an uneven load is suppressed, and a small diameter medical or industrial manipulator can be controlled with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, in order to demonstrate the structure of this invention in detail, embodiment shown below is only what was shown exemplarily using the rubber | gum artificial muscle which is an example of a small diameter actuator. Accordingly, the present invention should not be construed as being limited based on the description given in the following embodiments. The scope of the present invention includes all embodiments including various modifications and improvements of the following embodiments as long as they are within the scope of the invention described in the claims.

<First Embodiment>
FIG.
FIG. 1 is a perspective view schematically showing a rubber artificial muscle actuator 1 according to the first embodiment. The artificial rubber muscle actuator 1 is composed of a tubular elastic body 4 provided with locking members 2 and 3 at both ends and a braided reinforcing member 5, and the tubular elastic body 4 is elongated by controlling the air pressure inside the tubular elastic body 4. This is a drive mechanism that expands and contracts in the axial direction (in the direction of the central axis X in the figure) and changes the distance between the locking members 2 and 3. As a representative artificial rubber muscle actuator, for example, a McKibben actuator is known. The locking member 2 is connected to an air supply pipe, and air is supplied and exhausted into the tubular elastic body 4 through an air pressure application hole 6 provided in advance in the locking member 2.

  A displacement sensor is disposed on the surface of the braided reinforcing member 5 in the longitudinal axis direction (the central axis X direction in the figure). Details thereof will be described later. The displacement sensor includes a first sensor unit 7 and a second sensor unit 8, and one end of the first sensor unit 7 and one end of the second sensor unit 8 are connected in series by a turn-back mechanism 9 having conductivity. Has been. The other ends of the first and second sensor units 7 and 8 are connected to the first and second measurement electrodes 10 and 11 via lead wires, respectively. The first and second measurement electrodes 10 and 11 are connected to a power source, and a predetermined voltage can be applied to the entire displacement sensor 6. The amount of change in the electrical resistance value between the first measurement electrode 10 and the second measurement electrode 11 can be measured by a displacement meter. The displacement sensor expands and contracts in synchronization with the expansion / contraction amount of the artificial rubber muscle actuator 1 and shows a change in the electric resistance value corresponding to the expansion / contraction amount. Therefore, the expansion / contraction amount of the actuator can be identified from the change amount of the electric resistance value. it can.

  If a displacement sensor having a folded structure is arranged, the wiring of the sensor (that is, the measurement electrodes 10 and 11) can be taken out from only one side of the rubber artificial muscle actuator 1, so that it is not necessary to fold the wiring. Accordingly, it is not necessary to secure a wiring space, and accordingly, a plurality of actuators can be arranged densely in a narrow area, and the manipulator can be reduced in diameter. Further, since the displacement sensitivity is doubled by adopting the folded structure, it can function as a highly sensitive displacement sensor.

FIG.
2 is a cross-sectional view taken along line AA of the perspective view shown in FIG.

  The size of the artificial rubber muscle actuator 1 is not particularly limited, but when used as a drive mechanism for a small-diameter manipulator, the total length is, for example, 50 mm or more, preferably 50 mm to 300 mm, most preferably 100 mm to 200 mm. The diameter is, for example, 2 mm or less, preferably 0.5 to 2 mm, and most preferably 1 to 1.5 mm.

  The tubular elastic body 4 is constituted by an elastic member having an inner space, and the material thereof is not particularly limited. For example, a synthetic rubber elastic body such as nitrile rubber, silicone rubber, and butyl rubber is used.

  The tubular elastic body 4 is covered with a braided reinforcing member 5. The braided reinforcing member 5 serves to convert the circumferential expansion force of the tubular elastic body 4 into contraction in the longitudinal axis direction (the central axis X direction in the figure). Although there is no restriction | limiting in particular in the material of the braided reinforcement member 5, For example, high elastic modulus fibers, such as a polyamide fiber, a polyester fiber, glass fiber, an aramid fiber, are used.

  The locking members 2 and 3 are made of a metal material or a resin material. Both ends of the locking members 2 and 3 and the tubular elastic body 4 are fixed by an adhesive fixing or locking mechanism. The locking member 2 includes an air pressure application hole 6. The air supplied from the air supply pipe is supplied to the inner space of the tubular elastic body 4 through the air application hole 6, or the air in the tubular elastic body 4 is exhausted to the air supply pipe through the air application hole 6. . On the other hand, the locking member 3 has a sealed structure and prevents the air in the tubular elastic body 4 from leaking outside.

  Both ends of the first and second sensor parts 7 and 8 are fixed to the braided reinforcing member 5. Although there is no restriction | limiting in particular in the fixing method, For example, adhesion fixation is mentioned. The first and second sensor portions 7 and 8 are flexible sensors and can expand and contract in synchronization with the expansion and contraction of the elastic tubular body 4 and the braided reinforcing member 5. The first sensor unit 7 and the second sensor unit 8 have the same shape and the same structure in principle, and the constituent materials are also the same. However, it is possible to make a difference as appropriate within a range that can solve the problem of the present invention that suppresses the occurrence of an offset load described later.

FIG.
FIG. 3 is a perspective view showing a cross section of the first sensor unit 7 (the same applies to the second sensor unit 8). The first sensor unit 7 has a structure in which a conductor 31 on a thin film is sandwiched between first and second resin members 32 and 33.

  The conductor 31 is produced by dispersing a conductive filler, such as carbon, silver, copper, or nickel, in a thermoplastic resin, an elastomer, or a thermosetting resin, and adding various solvents and additives as appropriate. The conductor 31 is preferably formed by a carbon coating.

  The resin members 32 and 33 are produced by adding various solvents and additives as appropriate to natural rubber or synthetic rubber such as silicone rubber, urethane rubber, chloroprene rubber, acrylic rubber, or butadiene rubber. The resin members 32 and 33 are preferably made of silicone rubber. The resin members 32 and 33 serve as a base material for forming a thin film of the conductor 31 and also serve as a covering material for covering the thin film of the conductor 31.

  There is no restriction | limiting in particular in the manufacturing method, structure, and shape of the 1st sensor part 7, A design change is possible suitably. For example, as shown in FIG. 3, a conductor 31 is coated on a first resin member 33 made of silicone rubber (for example, carbon coating), and a second resin member 32 made of silicone rubber is bonded thereon. Alternatively, the conductor 31 may be injected and fixed to a resin member having an inner space. In this case, the conductor 31 has a structure enclosed in one resin member. Moreover, the shape of a sensor can be made into arbitrary shapes, such as a column shape and a polygonal column shape.

  For example, when silicone rubber coated with a conductive paint is stretched in the longitudinal direction, the density of carbon contained in the paint decreases and the electrical resistance value increases. Since the change in the electrical resistance value accurately corresponds to the amount of expansion / contraction in the longitudinal direction of the silicone rubber, the amount of expansion / contraction of the silicone rubber can be identified by detecting the amount of change in the electrical resistance value.

  One end of the first sensor unit 7 is electrically connected to one end of the second sensor unit 8 by a conductive folding mechanism 9. The folding mechanism 9 is, for example, a copper wire cord covered with an insulating resin member, and connects both sensor portions with a deflection so as not to hinder the expansion and contraction motion of the actuator 1. The other end of the first sensor unit 7 is connected to the first measurement electrode 10 via a lead wire.

FIG.
4 is a perspective view of a cross section taken along line BB in FIG. The first sensor unit 7 is arranged in parallel to the central axis X of the rubber artificial muscle actuator 1, and the second sensor unit 8 is from an arbitrary position Z ₁ of the first sensor unit 7 to the central axis X. Are arranged so as to be symmetric with respect to the central axis X on a line segment Y ₁ -Y ₂ that intersects perpendicularly.

  First, since the first sensor unit 7 and the second sensor unit 8 are arranged in parallel to the central axis X of the actuator, the expansion and contraction of each sensor unit can be interlocked with the expansion and contraction of the actuator. The expansion / contraction amount of the sensor unit can be regarded as the expansion / contraction amount of the actuator. Here, the amount of expansion / contraction of each sensor unit can be identified by detecting the amount of change in the electric resistance value. As a result, the amount of expansion / contraction of the actuator can be identified from the amount of change in the electric resistance value.

Next, the second sensor unit 8 is an axis with respect to the central axis X on a line segment Y ₁ -Y ₂ perpendicular to the central axis X from an arbitrary position Z ₁ of the first sensor unit 7. By arranging so as to be symmetric, it is possible to suppress the occurrence of an offset load. For the rubber artificial muscle actuator 1, the sensor having the folded structure is a foreign substance. When the sensor is attached to the actuator surface, a deviation occurs between the center axis of the actuator and the center axis of the actuator. As a result, the actuator is pulled or bent. In order to provide a small-diameter medical or industrial manipulator, it is necessary to reduce the diameter of the actuator itself as a drive control unit of the manipulator. The problem of pulling and bending associated with the telescopic movement of the arm is exacerbated. In this regard, the rubber artificial muscle actuator 1 according to the first embodiment has the displacement sensor having the folded structure arranged symmetrically with respect to the central axis X, so that the “displacement” of the center of gravity at each position is canceled out. Overall, the center of gravity is maintained on the central axis. As a result, it is possible to provide a linear motion actuator in which the occurrence of an unbalanced load on the actuator is suppressed and the pulling and bending associated with the expansion and contraction motion of the actuator are unlikely to occur.

  Of course, “center axis”, “parallel”, “vertically intersecting line segment”, and “axial symmetry” do not strictly follow the mathematical definition, and the effect of suppressing the occurrence of uneven load This is a concept that can be extended according to the actual situation of each individual actuator.

<Second Embodiment>
FIG.
FIG. 5 is a perspective view schematically showing the artificial rubber muscle actuator 1 according to the second embodiment.

  The rubber artificial muscle actuator 1 according to the second embodiment includes a first displacement sensor 50 having a folded structure constituted by a first sensor unit 51 and a second sensor unit 52, and a first sensor unit 55 and And a second displacement sensor 60 having a folded structure constituted by the second sensor unit 56. The first displacement sensor 50 is arranged in parallel to the central axis X of the rubber artificial muscle actuator 1, and the second displacement sensor 60 is from each position of the first displacement sensor 50 to the central axis X. They are arranged so as to be axially symmetric with respect to the central axis X on a perpendicularly intersecting line segment.

FIG.
6 is a cross-sectional view taken along line CC of the perspective view shown in FIG.

The first sensor portion 51 of the first displacement sensor 50 is arranged symmetrically with respect to the central axis X on the line segment Y ₁ -Y ₁ with the second sensor portion 56 of the second displacement sensor 60. Yes. The second sensor portion 52 of the first displacement sensor 50, disposed in axial symmetry with respect to the central axis X on the first sensor unit 55 and a line segment Y ₂ -Y ₂ of the second displacement sensor 60 Has been.

  By arranging two independent displacement sensors having a folded structure in axial symmetry with respect to the central axis of the actuator, it is possible to provide an actuator that can suppress the occurrence of an offset load and is resistant to failures such as disconnection. That is, in a small-diameter actuator, the displacement sensor attached to the actuator has an extremely fine shape, and there is a concern about failure due to disconnection or the like. In particular, medical and industrial thin manipulators require constant precision control during their use, so if a failure due to disconnection or the like occurs before the service life, the reliability of the product may be impaired. Is expensive. In this regard, the artificial rubber muscle actuator in the second embodiment is provided with two independent displacement sensors, so that one of the displacement sensors falls into a failure due to disconnection or the like before the service life. However, since the other displacement sensor can continue to precisely control the amount of expansion and contraction of the actuator, it is possible to provide a highly reliable small-diameter manipulator.

<Third Embodiment>
Further, as an application of the second embodiment, by arranging three or more independent displacement sensors having a folded structure in parallel to the central axis X so that the offset load is suppressed as a whole, further failure can be caused. A strong actuator can be provided. In this case, it is possible to set the service life of the actuator itself longer by being strong in failure, and the product life can be extended.

  Specifically, when three displacement sensors are arranged, each displacement sensor is arranged in parallel to the central axis at intervals of 120 degrees on the circumference of the artificial rubber muscle actuator 1, thereby suppressing the actuator's uneven load. can do.

<Fourth Embodiment>
FIG.
FIG. 7 is a perspective view schematically showing the artificial rubber muscle actuator 1 according to the fourth embodiment.

  The artificial rubber muscle actuator 1 according to the fourth embodiment is a two-way reciprocating folded structure including a first sensor unit 71, a second sensor unit 72, a third sensor unit 73, and a fourth sensor unit 74. A displacement sensor. And the 1st sensor part 71 is arranged in parallel to central axis X of rubber artificial muscle actuator 1, and the 2nd sensor part 72 is relative to said central axis X from each position of the 1st sensor part 71. They are arranged so as to be axially symmetric with respect to the central axis X on a perpendicularly intersecting line segment. Further, the third sensor unit 73 is arranged in parallel to the central axis X of the rubber artificial muscle actuator 1, and the fourth sensor unit 74 is arranged from each position of the third sensor unit 73 with respect to the central axis X. Are arranged so as to be axially symmetric with respect to the central axis X on line segments that intersect perpendicularly.

  The first sensor unit 71 and the second sensor unit 72 are connected in series by a folding mechanism 76 having one end at each end, and the second sensor unit 72 and the third sensor unit 73 are respectively connected to one end. Are connected in series by a folding mechanism 77 having conductivity, and each of the third sensor portion 73 and the fourth sensor portion 74 is connected in series by a folding mechanism 78 having conductivity. Each folding mechanism connects both sensor portions with a deflection so as not to obstruct expansion and contraction of the actuator. The other ends of the first sensor unit 71 and the fourth sensor unit 74 are connected to the measurement electrodes 10 and 11 via lead wires, respectively.

FIG.
8 is a cross-sectional view taken along the line DD in the perspective view shown in FIG.

The first sensor unit 71 is arranged symmetrically with respect to the central axis X on the line segment Y ₁ -Y ₁ with the second sensor unit 72. The third sensor unit 73 is arranged symmetrically with respect to the central axis X on the line segment Y ₂ -Y ₂ with the fourth sensor unit 74.

  By disposing the displacement sensor having a two-way reciprocation structure in axial symmetry with respect to the central axis of the actuator, it is possible to provide an actuator with reduced detection load and high detection sensitivity. That is, since the four sensor units constituting the displacement sensor are arranged in parallel to the central axis, the electric resistance value changes according to the expansion and contraction of the actuator. Since the four sensor units are connected in series by the folding mechanism, the amount of change in the electrical resistance value is approximately twice that of a one-reciprocation displacement sensor composed of two sensor units. Therefore, the sensitivity of the displacement sensor having the two reciprocating structure is improved about twice as compared with the displacement sensor having the one reciprocating structure, and a slight expansion / contraction amount of the actuator can be detected reliably and accurately.

  Medical or industrial thin manipulators require fine and complex operations. For example, a medical manipulator is required to perform a precise and flexible manipulation operation in a complicated and complicated space in a living tissue. By using an actuator equipped with a position sensor having two reciprocating structures as a drive mechanism for a manipulator, the manipulator drive distance can be reduced, and a highly functional thin manipulator capable of finer and more complex operations. Can be provided.

<Fifth Embodiment>
FIG.
FIG. 9 is a perspective view schematically showing the artificial rubber muscle actuator 1 according to the fifth embodiment.

  The artificial rubber muscle actuator 1 according to the fifth embodiment has a two-way reciprocation structure constituted by a first sensor unit 81, a second sensor unit 82, a third sensor unit 83, and a fourth sensor unit 84. The first displacement sensor 85 having the same structure as that of the first sensor unit 91, the second sensor unit 92, the third sensor unit 93, and the fourth sensor unit 94. A second displacement sensor 95. The first displacement sensor 85 is arranged in parallel to the central axis X of the rubber artificial muscle actuator, and the second displacement sensor 95 is perpendicular to the central axis X from each position of the first displacement sensor. They are arranged so as to be axially symmetric with respect to the central axis X on the intersecting line segments.

FIG.
10 is a cross-sectional view taken along line EE of the perspective view shown in FIG.

The first sensor portion 81 of the first displacement sensor 85 is arranged symmetrically with respect to the central axis X on the line segment Y ₁ -Y ₁ with the fourth sensor portion 94 of the second displacement sensor 95. Yes. The second sensor portion 82 of the first displacement sensor 85 is arranged symmetrically with respect to the central axis X on the line segment Y ₂ -Y ₂ with the third sensor portion 93 of the second displacement sensor 95. Has been. The third sensor unit 83 of the first displacement sensor 85 is arranged symmetrically with respect to the central axis X on the line segment Y ₃ -Y ₃ with the second sensor unit 92 of the second displacement sensor 95. Has been. Furthermore, the fourth sensor portion 84 of the first displacement sensor 85 is symmetric with respect to the central axis X on the line segment Y ₄ -Y ₄ with the first sensor portion 91 of the second displacement sensor 95. Is arranged.

  By arranging two independent displacement sensors with two reciprocating folding structures symmetrically with respect to the central axis of the actuator, the occurrence of unbalanced load is suppressed, detection sensitivity is high, and failures such as disconnection are prevented. A strong actuator can be provided. That is, by using the actuator according to the fifth embodiment as a drive control mechanism for a medical or industrial thin manipulator, a high-performance and high-resistance thin film with a very small driving limit distance and a long service life. A diameter manipulator can be provided.

<Sixth Embodiment>
Further, as an application of the fifth embodiment, by arranging three or more independent displacement sensors having two reciprocating folding structures in parallel to the central axis X so that the uneven load is suppressed as a whole, An actuator with higher detection sensitivity and resistance to failure can be provided.

  Specifically, when three displacement sensors having two reciprocating structures are arranged, the displacement sensors are arranged parallel to the central axis X at intervals of 120 degrees on the circumference of the rubber artificial muscle actuator 1. Can be suppressed.

<Seventh Embodiment>
The rubber artificial muscle actuator 1 in the seventh embodiment includes a displacement sensor having a folding structure of at least three reciprocations, and each sensor portion constituting the displacement sensor is parallel to the central axis of the rubber artificial muscle actuator. The two sensor parts that are arranged and that constitute each reciprocating structure are arranged so as to be axially symmetric with respect to the central axis on a line segment perpendicular to the central axis of the rubber artificial muscle actuator. .

  For example, a displacement sensor having a three-way structure includes six sensor units, five folding mechanisms, and two measurement electrodes connected to the start and end. The displacement sensor of the three-way structure has a theoretically amplified detection sensitivity three times that of the one-way structure. Since the six sensor parts constitute a pair and are arranged in an axial symmetry (that is, the three sensor parts are arranged in an axial symmetry on different line segments Y-Y), the entire actuator has an offset load. Occurrence is suppressed.

<Eighth Embodiment>
The rubber artificial muscle actuator 1 in the eighth embodiment includes first and second displacement sensors having a folding structure of at least three reciprocations, and the first displacement sensor is relative to the central axis of the rubber artificial muscle actuator. The second displacement sensor is arranged so as to be symmetric with respect to the central axis on a line segment perpendicular to the central axis from each position of the first displacement sensor. .

  For example, by arranging two independent displacement sensors having three reciprocating structures in an axisymmetric manner, it is possible to provide an actuator that suppresses the occurrence of an offset load, has high detection sensitivity, and is resistant to failures such as disconnection. .

<Ninth Embodiment>
Further, as an application of the eighth embodiment, by arranging three or more independent displacement sensors having three reciprocating folding structures in parallel to the central axis X so as to suppress the bias load as a whole, An actuator with higher detection sensitivity and resistance to failure can be provided.

  Specifically, when three displacement sensors having three reciprocating structures are arranged, the displacement sensors are arranged parallel to the central axis X at intervals of 120 degrees on the circumference of the rubber artificial muscle actuator 1. Can be suppressed.

Table 1 below shows the relationship of the rubber artificial muscle actuator 1 in the first to ninth embodiments. The rubber artificial muscle actuators 1 in the first to ninth embodiments are classified according to the number of reciprocations in the sensor structure and the number of sensors mounted. These common effects are suppression of uneven load. The number of reciprocations within the sensor structure improves the sensitivity of the sensor, and the number of sensors mounted improves the resistance of the sensor (becomes more resistant to failure).

  Theoretically, the higher the number of reciprocations and the greater the number of mountings, the higher the quality of the actuator can be provided, but even the rubber artificial muscle actuator in the first embodiment in which one actuator having a single reciprocating structure is mounted has a small diameter. It is possible to sufficiently provide the accuracy and resistance required for an ultra-fine actuator mounted on a manipulator. And, since the ultra-fine actuator has a small surface area, increasing the number of reciprocations and mounting of the displacement sensor reduces the conductor area of each sensor unit, thereby reducing the degree of expansion and contraction of each sensor unit and the change in electrical resistance value. There is concern that the strict correlation between the two will decline. In addition, an extremely fine conductor is easily disconnected. Therefore, when the actuator is limited to an extremely thin actuator, ideally, one having two or less displacement sensors having two or less reciprocating structures is most preferable.

FIG.
FIG. 11 is a schematic diagram of a drive mechanism 100 using two rubber artificial muscle actuators 1 (hereinafter referred to as rubber artificial muscle actuators 101 and 102) in the first to ninth embodiments described above.

  In the drive mechanism 100, two artificial rubber muscle actuators 101 and 102 are fixed to a fixed substrate 190. The locking members 103 and 104 are connected to the wire 105, and the wire 105 is hooked on the pulley 106. An operation tool 110 is fixed to the pulley 106, and the operation tool 110 is rotated up and down by the rotational movement of the pulley 106. Accordingly, the operation tool 110 can be turned up and down as desired by controlling the expansion and contraction of the artificial rubber muscle actuators 101 and 102. The rubber artificial muscle actuators 101 and 102 are connected to the pressure control means 120 via air supply pipes 111 and 112, respectively. The pressure control means 120 includes an electropneumatic regulator 130 and a compressor 140.

  The artificial rubber muscle actuators 101 and 102 each include a displacement sensor on the surface thereof. As the displacement sensor, any one of the displacement sensors of the first to ninth embodiments described above is appropriately selected. Each expansion / contraction amount of the actuators 101 and 102 is output as a change amount of the electric resistance value by the circuits 150 and 160, respectively. The computing means (PC) 170 identifies the expansion / contraction amount of each actuator from the output change amount of the electrical resistance value. The PC 170 calculates the difference between the expansion / contraction amount of each actuator necessary for the desired vertical rotation of the operation tool 110 input from the operation means 180 and the expansion / contraction amount of each actuator at the present time, and calculates the difference data Based on the above, a control command for executing a desired vertical rotation of the operation tool 110 is transmitted to the pressure control means 120. The pressure control means 120 controls the air pressure inside the actuator based on the control command, and the desired operation tool 110 is turned up and down by appropriately controlling the expansion and contraction amount of each actuator. By assembling such a feedback group, the operation tool 110 attached to the pulley 106 can be easily positioned.

  By forming the displacement sensor integrally with the actuator, the entire system (particularly, the actuator and the rotating unit) can be reduced in size. Further, since the displacement sensor of each actuator has a folded structure, the measurement electrode (wiring) can be taken out from one end of the actuator, so that it is not necessary to fold the wiring, and the diameter of the entire system can be further reduced.

  In FIG. 11, the two artificial rubber muscle actuators 101 and 102 each have an independent control mechanism and can be controlled separately. However, each actuator does not necessarily need to be controlled independently, and the control mechanism of each actuator may be linked. For example, it is possible to control the two artificial rubber muscle actuators 101 and 102 by providing a displacement sensor only in the artificial rubber muscle actuator 101 and outputting a varying electric resistance value. In this case, the displacement sensor on the actuator 102 and the circuit 160 for outputting the electric resistance value detected by the displacement sensor can be omitted, so that cost reduction and space saving can be realized.

FIG.
FIG. 12 is a schematic diagram of a medical treatment instrument 200 using the rubber artificial muscle actuator 1 according to any one of the first to ninth embodiments.

  The medical treatment instrument 200 includes a small-diameter manipulator 210, an operation unit 220 that drives the small-diameter manipulator 210, a calculation unit 230 that controls the internal pressure of the rubber artificial muscle actuator based on the drive signal input by the operation unit 220, Pressure control means for applying air to the inside of the rubber artificial muscle actuator based on a command from the calculation means 230. The pressure control means includes an electropneumatic regulator 240 and a compressor 250.

  The small-diameter manipulator 210 includes a plurality of artificial rubber muscle actuators 201, an insertion arm 260 having the artificial rubber muscle actuator 201 therein, and an operation tool 270 attached to the distal end of the insertion arm 260.

  The displacement sensor of any of the first to ninth embodiments described above is installed on the surface of each actuator 201, and the amount of expansion / contraction of each actuator 201 can be detected as the amount of change in electrical resistance value.

  Further, a bending drive means 280 may be provided at the distal end of the insertion arm 260. The bending drive means 280 includes, for example, first to third joints 281, 282, and 283 that perform different bending motions, and a pulley 271 in which an operation tool 270 is fixed to the central axis at the tip of the third joint 283. Is attached.

  Since each of the first to third joints 281, 282, 283 and the pulley 271 is controlled by a set of two rubber artificial muscle actuators 201, a total of eight sets of four rubber artificial muscle actuators 201 are inserted into the insertion arm 260. (Only two are shown for convenience). Each of these eight sets of four artificial rubber muscle actuators includes the displacement sensor according to any of the first to ninth embodiments described above on its surface, and the expansion / contraction amount of the actuator is output as the change amount of the electric resistance value. . As described above, the same control is possible even if only one of the two actuators has a built-in resistor.

FIG.
FIG. 13 is a schematic diagram for explaining the drive mechanism of the bending drive means 280 of FIG. The first joint 281 is controlled by two rubber artificial muscle actuators 201. Rubber artificial muscle actuators 201 are connected to both ends of the first joint 281 via wires 205, respectively. The joint 281 can be rotated in the direction of the arrow in the figure by the expansion and contraction of the two actuators 201. Similarly, rubber artificial muscle actuators 201 are connected to both ends of the second joint 282 via wires 205, respectively, and the second joint 282 is moved in the direction indicated by the arrow in FIG. Can be rotated in the direction.

FIG.
FIG. 14 is a schematic diagram for further explaining the drive mechanism of the bending drive means 280 of FIGS.

  The first joint 281 is rotated with respect to the Z axis in the figure by two actuators 201. Next, the second joint 282 is rotated with respect to the Y axis in the figure by two separate actuators 201 different from the actuator that controls the rotation of the first joint 281. Finally, the third joint 283 is rotated with respect to the X axis in the figure by two separate actuators 201 different from the actuator that controls the rotation of the first and second joints 281 and 282.

  Since the first to third joints 281, 282, and 283 rotate with respect to the respective axes in the three-dimensional space, they can be directed in all directions in the three-dimensional space as a whole. Precise and free manipulation is possible in the complicated space. Also, by mounting a displacement sensor integrated rubber artificial muscle actuator on the tip of a medical treatment instrument (medical manipulator) inserted into the abdominal cavity, etc., the sensor and wiring can directly touch the living tissue in the abdominal cavity. The safety is improved.

  As described above, according to the present invention, a multi-function or multi-dimension can be obtained while accurately grasping a local operation on various objects (organs, blood vessels, etc.) in a living body such as a narrow insertion space, particularly an abdominal cavity. Can be controlled freely. In particular, when multiple pairs of actuators corresponding to each of the articulated drive shafts arranged at the distal end of the medical manipulator are driven in conjunction with each other, it is possible to determine in real time and accurately whether the multi-function or complex operation by each actuator is appropriate. Can be confirmed.

  The present invention is not limited to the rubber artificial muscle or the pneumatic control actuator described in the above-described embodiment, and similarly to other small-diameter actuators (for example, wire drive type) within the scope of the above-described gist. You may apply.

The perspective view which showed typically the rubber artificial muscle actuator 1 in 1st Embodiment Sectional drawing along line AA of the perspective view shown in FIG. The perspective view which showed the cross section of the 1st sensor part 7 (the 2nd sensor part 8 is also the same). FIG. 1 is a perspective view of a cross section taken along line BB in FIG. The perspective view which showed typically the rubber artificial muscle actuator 1 in 2nd Embodiment Sectional drawing along line CC of the perspective view shown in FIG. The perspective view which showed typically the rubber artificial muscle actuator 1 in 4th Embodiment Sectional drawing along line DD of the perspective view shown in FIG. The perspective view which showed typically the rubber artificial muscle actuator 1 in 5th Embodiment Sectional drawing along line EE of the perspective view shown in FIG. Schematic diagram of a driving mechanism 100 using two rubber artificial muscle actuators 1 according to any of the first to ninth embodiments. The schematic diagram of the medical treatment tool 200 using the rubber artificial muscle actuator 1 in any one of 1st-9th embodiment. Schematic diagram for explaining the drive mechanism of the bending drive means 280 of FIG. Schematic diagram for further explaining the drive mechanism of the bending drive means 280 of FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rubber artificial muscle actuator, 2 ... Locking member, 3 ... Locking member, 4 ... Tubular elastic body, 5 ... Braided reinforcement member, 6 ... Hole for air application, DESCRIPTION OF SYMBOLS 7 ... 1st sensor part, 8 ... 2nd sensor part, 9 ... Folding mechanism, 10 ... Measuring electrode, 11 ... Measuring electrode, 31 ... Conductor, 32 ... resin member, 33 ... resin member, 50 ... first displacement sensor, 51 ... first sensor unit, 52 ... second sensor unit, 55 ... first Sensor unit 56 ... second sensor unit 60 ... second displacement sensor 71 ... first sensor unit 72 ... second sensor unit 73 ... third Sensor unit 74, fourth sensor unit, 76 ... first folding mechanism, 77 ... second folding mechanism, 78 ... third folding mechanism, 8 ... 1st sensor part, 82 ... 2nd sensor part, 83 ... 3rd sensor part, 84 ... 4th sensor part, 85 ... 1st displacement sensor, 91 ... 1st sensor part, 92 ... 2nd sensor part, 93 ... 3rd sensor part, 94 ... 4th sensor part, 95 ... 2nd displacement sensor, 100 ... Drive mechanism, 101, 102 ... Rubber artificial muscle actuator, 103, 104 ... Locking member, 105 ... Wire, 106 ... Pulley, 110 ... Operating tool, 111, 112 ..Piping for air supply, 120 ... pressure control means, 130 ... electro-pneumatic regulator, 140 ... compressor, 150,160 ... circuit, 170 ... calculation means, 180 ... operation means, 190・ ・ ・ Fixed substrate, 200 ・ ・ ・ Medical treatment instrument, 201 ・ ・ ・ Rubber artificial muscle actuator, 210 ・ ・ ・ Small diameter manipulator, 220 ・ ・ ・ Operating means, 230 ・ ・ ・Means 240 ... electro-pneumatic regulator 250 ... compressor 260 ... insertion arm 270 ... operation tool 271 ... pulley 280 ... bending drive means 281 ... first 282 ... second joint, 283 ... third joint.

Claims (6)

Comprising a displacement sensor having a folded structure constituted by first and second sensor portions;
The first sensor unit is arranged in parallel to the central axis of the actuator, and the second sensor unit is located on the central axis on a line segment perpendicular to the central axis from each position of the first sensor unit. A small-diameter actuator characterized in that the occurrence of an offset load is suppressed by being arranged so as to be axially symmetric. Comprising a displacement sensor having a two-way reciprocation structure constituted by first to fourth sensor portions;
The first sensor unit is arranged in parallel to the central axis of the small-diameter actuator, and the second sensor unit is located on a line segment perpendicular to the central axis from each position of the first sensor unit. The third sensor unit is arranged parallel to the central axis of the small-diameter actuator, and the fourth sensor unit is arranged from each position of the third sensor unit. A small-diameter actuator characterized by suppressing the occurrence of an offset load by being arranged so as to be axially symmetric with respect to the central axis on a line segment perpendicular to the central axis. Comprising first and second displacement sensors having a folded structure of at least three reciprocations;
The first displacement sensor is arranged in parallel to the central axis of the small-diameter actuator, and the second displacement sensor is on the line segment perpendicular to the central axis from each position of the first displacement sensor. A small-diameter actuator characterized by suppressing the occurrence of an offset load by being arranged so as to be symmetric with respect to an axis.   The displacement sensor having the folded structure includes first and second sensor portions having flexibility in which a thin film-like conductor is sandwiched between first and second resin members having electrical insulation and elasticity; A conductive folding mechanism for connecting one end of each of the first and second sensor units in series; and first and second measurement electrodes connected to the other ends of the first and second sensor units; The first and second measurement electrodes are connected to an electric circuit, and the expansion / contraction amount of the small-diameter actuator is detected from a change in the electric resistance value between the electrodes. The small diameter actuator of any one of 1-3. The small-diameter actuator according to any one of claims 1 to 4,
An insertion arm having the small-diameter actuator therein;
An operation tool attached to the tip of the insertion arm;
The small-diameter manipulator, wherein driving of the operation tool is controlled by expansion and contraction of the small-diameter actuator.   The thin manipulator according to claim 5, wherein two or more thin actuators are provided, and each actuator is individually controlled.

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